Structured surfaces have been used in various applications for optical benefits, surface energy modification, adhesive tack control, and drag reduction. For example, prismatic structures on the surface of photovoltaic panels reduce reflection and direct more light towards the silicon cells, thus increasing power output. Similar prismatic structures promote fluid flow over a surface resulting in reduced drag when applied to an automobile, boat, or the like, or to wind or water turbine blades.
With the rising costs of conventional power generation based on burning fossil fuels (e.g., oil and coal based power plants), and the desire to reduce associated greenhouse gases, investments into non-conventional sources of power have increased. For example, the U.S. Department of Energy has invested heavily into the research and development of solar power generation (e.g., solar energy based hot water and electricity generation). One such non-conventional source of power generation is the use of photovoltaic cells to convert solar light energy into electricity. Solar light energy has also been used to directly or indirectly heat water for residential and commercial use. Along with this increased level of interest, there is a need for improving the efficiency at which such non-conventional solar energy technologies can absorb light energy and thereby increase the amount of solar energy available for use. Therefore, it is desirable for an antireflective surface to be placed between the energy conversion device and the sun to reduce surface reflections and increase transmission. A common problem associated with anti-reflective surfaces is soiling and thus the need for a coating on the anti-reflective surface which reduces or prevents the accumulation of dirt, sand, oil, etc. . . .